Preservatives, pesticides, antivirals, antifungals, antibacterials, xenobiotics, hydrophobic drugs or pharmaceuticals, anti-protozoal, antimicrobials, antibiotics, and biocides (referred to herein collectively as antimicrobial agents) are commonly added to formulations to provide antimicrobial formulations for use on animate (e.g., skin, hair, and body of a user) and inanimate surfaces (e.g., countertops, floors, glass), as well as in agricultural and industrial applications. Although antimicrobial agents are useful, many antimicrobial agents are hydrophobic and current mixing procedures have multiple problems such as poor solubility and dispersibility of the antimicrobial agents within the formulation, which can lead to decreased efficacy, and which can waste time, energy, and money for manufacturers of these formulations.
Specifically, formulations are currently prepared in a batch-type process, either by a cold mix or a hot mix procedure. The cold mix procedure generally consists of multiple ingredients (including the antimicrobial agents) or phases being added into a kettle in a sequential order with agitation being applied via a blade, baffles, or a vortex. The hot mix procedure is conducted similarly to the cold mix procedure with the exception that the ingredients or phases are generally heated above room temperature, for example to temperatures of from about 40 to about 100° C., prior to mixing, and are then cooled back to room temperature after the ingredients and phases have been mixed. In both procedures, antimicrobial agents are added to the other ingredients manually by one of a number of methods including dumping, pouring, and/or sifting.
Historically, these conventional batch-type methods have not been very effective in mixing hydrophobic antimicrobial agents into aqueous-type formulations. As such, hydrophobic antimicrobial agents have been added into emulsions delivery vehicles or oils. The produced-emulsions have not been sufficiently mixed into the formulation, hindering the antimicrobial activity of the antimicrobial agent. Furthermore, the antimicrobial agents are not well dispersed within the emulsions and/or formulation, thereby forming larger particle-sized agents that can also lead to less antimicrobial activity against microbes.
These conventional methods of mixing antimicrobial agents into formulations have several additional problems. For example, as noted above, all ingredients are manually added in a sequential sequence. Prior to adding the ingredients, each needs to be weighed, which can create human error. Specifically, as the ingredients need to be weighed one at a time, misweighing can occur with the additive amounts. Furthermore, by manually adding the ingredients, there is a risk of spilling or of incomplete transfers of the ingredients from one container to the next.
One other major issue with conventional methods of mixing antimicrobial agents into formulations is that batching processes require heating times, mixing times, and additive times that are entirely manual and left up to the individual compounders to follow the instructions. These practices can lead to inconsistencies from batch-to-batch and from compounder to compounder. Furthermore, these procedures require several hours to complete, which can get extremely expensive.
Based on the foregoing, there is a need in the art for a mixing system that provides ultrasonic energy to enhance the mixing of antimicrobial agents, particularly hydrophobic antimicrobial agents, into formulations. Furthermore, it would be advantageous if the system could be configured to enhance the cavitation mechanism of the ultrasonics, thereby increasing the probability that the antimicrobial agents will be effectively mixed/dispersed within and throughout the formulations.